The present invention relates generally to combine threshing machines, particularly the step performed by such threshing machines wherein straw and chaff are chopped and scattered about behind the threshing machine during the harvesting operation, and relates more particularly to a device attached to a combine threshing machine which performs a secondary chopping and scattering operation on straw and chaff that exit the rear of the threshing machine during the harvesting operation.
Threshing machines of various types are in common use today. These various types of threshing machines function in slightly different manners to perform basically identical functions: (1) harvesting or removing the grain from the ground; (2) threshing or separating the grain from the husk, straw and chaff; and (3) collecting the grain while leaving behind the straw and chaff. Various devices have been devised to scatter the remaining straw and chaff behind the threshing machine in order to prevent the build-up of a concentration of straw and chaff along a narrow path behind the threshing machine. These various devices have commonly taken the form of a pair of rotating wheels, commonly called straw spreaders, positioned at the rear of the combine somewhat in the flow of straw and chaff exiting the rear of the combine. Due to the nature of a single straw spreading operation, these "straw spreaders" have proved basically ineffective in chopping and scattering both chaff and straw due to the difference in characteristics of chaff and straw.